Leprosy (Hansen’s Disease)

What is leprosy?

Leprosy is a chronic infectious disease which has predilection for the skin, nerves and mucous membrane. The disease is caused by Mycobacterium leprae, which is a species of bacteria that has similarities with the bacteria that causes tuberculosis (TB). It is also known as Hansen’s disease and mainly seen in tropical and subtropical countries. The condition is broadly classified in to two types – lepromatous leprosy and tuberculoid leprosy.

What are the symptoms of leprosy?

Although it is a systemic infection, leprosy present predominantly as an infection of the skin, the upper respiratory tract and peripheral nerves. The characteristic feature of this disease is its predilection to affect the surface of the body, particularly the cooler areas. Warm areas like axilla, usually remain unaffected. The incubation period for the disease is 2 to 5 years.

The skin lesions show a lighter hue then normal skin. The lesions show decreased or loss of sensations on touch or heat. The lesions do not heal for several months. One of the characteristic features of leprosy is its effect on nerves. Irritation nerve endings with abnormal sensations may be experienced. Eventually there is severe disfigurement of hands and feet, which is not due to the disease itself but due to the damage and misuse which follows loss of pain sensation.

Lining of the nose is severely involved. Systemic symptoms such as malaise, fever and joint pain may occur. Occasionally rhinitis and tender lymph nodes may be noticed. Leonine facies is seen in certain cases of leprosy which characterized by loss of lateral portion of eyebrow and thickened and corrugated facial skin.

What causes leprosy?

Mycobacterium leprae are the causative bacteria responsible for leprosy. The source of infection is not the skin but mainly from nasal secretions of patient with lepromatous leprosy. The disease is endemic in areas with hot and moist climate. The disease is also more prevalent in poor tropical countries. Certain countries in southeast Asia, like India, and west Africa, like Nigeria, together constitute the vast majority of leprosy cases globally. India accounts for about one third of all registered cases throughout the world.

Poor hygiene, malnutrition and contaminated water supplies are also few contributing factors as they lower immunity. The disease is also believed to be linked with certain genetic factors and majority of the people are naturally immune to it. Diseases like HIV/AIDS also increase susceptibility to develop leprosy.

How is leprosy treated?

Dapsone is the drug of choice for the treatment of leprosy. The other anti-leprosy drugs are rifampicin, ethionamide and clofazimine. Multidrug drug therapy is often the best treatment for leprosy. A combination of these drugs can be used for drug-resistant cases. Rifampicin and dapsone are preferred in the treatment tuberculoid leprosy, where as rifampicin, clofazimine and dapsone for 12 months is the general treatment for lepromatous leprosy. The disease may take between two to ten years to completely resolve, depending on the subtype of leprosy. Anti-inflammatory drugs are given in reactionary phases of the disease. Surgery is recommended in cases with various deformities.